Diversity of soil yeasts isolated from South Victoria Land, Antarctica
L. Connell, R. Redman, S. Craig, G. Scorzetti, M. Iszard, R. Rodriguez
2008, Microbial Ecology (56) 448-459
Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken from sites spanning a diversity of soil habitats that were not directly associated...
Importance of agricultural landscapes to nesting burrowing owls in the Northern Great Plains, USA
M. Restani, J.M. Davies, W.E. Newton
2008, Landscape Ecology (23) 977-987
Anthropogenic habitat loss and fragmentation are the principle factors causing declines of grassland birds. Declines in burrowing owl (Athene cunicularia) populations have been extensive and have been linked to habitat loss, primarily the decline of black-tailed prairie dog (Cynomys ludovicianus) colonies. Development of habitat use models is a research priority...
A double-observer method for reducing bias in faecal pellet surveys of forest ungulates
K.J. Jenkins, B.F.J. Manly
2008, Journal of Applied Ecology (45) 1339-1348
1. Faecal surveys are used widely to study variations in abundance and distribution of forest-dwelling mammals when direct enumeration is not feasible. The utility of faecal indices of abundance is limited, however, by observational bias and variation in faecal disappearance rates that obscure their relationship to population size. We developed...
Assessing streamflow characteristics as limiting factors on benthic invertebrate assemblages in streams across the western United States
C.P. Konrad, A.M.D. Brasher, J. T. May
2008, Freshwater Biology (53) 1983-1998
1. Human use of land and water resources modifies many streamflow characteristics, which can have significant ecological consequences. Streamflow and invertebrate data collected at 111 sites in the western U.S.A. were analysed to identify streamflow characteristics (magnitude, frequency, duration, timing and variation) that are probably to limit characteristics of benthic...
Development of a three-dimensional, regional, coupled wave, current, and sediment-transport model
J.C. Warner, C. R. Sherwood, R. P. Signell, C. K. Harris, H.G. Arango
2008, Computers & Geosciences (34) 1284-1306
We are developing a three-dimensional numerical model that implements algorithms for sediment transport and evolution of bottom morphology in the coastal-circulation model Regional Ocean Modeling System (ROMS v3.0), and provides a two-way link between ROMS and the wave model Simulating Waves in the Nearshore (SWAN) via the Model-Coupling Toolkit. The...
Calculating wave-generated bottom orbital velocities from surface-wave parameters
P.L. Wiberg, C. R. Sherwood
2008, Computers & Geosciences (34) 1243-1262
Near-bed wave orbital velocities and shear stresses are important parameters in many sediment-transport and hydrodynamic models of the coastal ocean, estuaries, and lakes. Simple methods for estimating bottom orbital velocities from surface-wave statistics such as significant wave height and peak period often are inaccurate except in very shallow water. This...
Application of sedimentary-structure interpretation to geoarchaeological investigations in the Colorado River Corridor, Grand Canyon, Arizona, USA
A.E. Draut, D. M. Rubin, J.L. Dierker, H.C. Fairley, R.E. Griffiths, J.E. Hazel Jr., R. E. Hunter, K. Kohl, L.M. Leap, F.L. Nials, D.J. Topping, M. Yeatts
2008, Geomorphology (101) 497-509
We present a detailed geoarchaeological study of landscape processes that affected prehistoric formation and modern preservation of archaeological sites in three areas of the Colorado River corridor in Grand Canyon, Arizona, USA. The methods used in this case study can be applied to any locality containing unaltered, non-pedogenic sediments and,...
A coupled model approach to reduce nonpoint-source pollution resulting from predicted urban growth: A case study in the Ambos Nogales watershed
L.M. Norman, D.P. Guertin, M. Feller
2008, Urban Geography (29) 496-516
The development of new approaches for understanding processes of urban development and their environmental effects, as well as strategies for sustainable management, is essential in expanding metropolitan areas. This study illustrates the potential of linking urban growth and watershed models to identify problem areas and support long-term watershed planning. Sediment...
On the in situ aqueous alteration of soils on Mars
Ronald Amundson, S. Ewing, W. Dietrich, B. Sutter, J. Owen, O. Chadwick, K. Nishiizumi, Michelle Ann Walvoord, C. McKay
2008, Geochimica et Cosmochimica Acta (72) 3845-3864
Early (>3 Gy) wetter climate conditions on Mars have been proposed, and it is thus likely that pedogenic processes have occurred there at some point in the past. Soil and rock chemistry of the Martian landing sites were evaluated to test the hypothesis that in situ aqueous alteration and downward...
Distinguishing solid bitumens formed by thermochemical sulfate reduction and thermal chemical alteration
S.R. Kelemen, C.C. Walters, P.J. Kwiatek, M. Afeworki, M. Sansone, H. Freund, R.J. Pottorf, H.G. Machel, T. Zhang, G.S. Ellis, Y. Tang, K. E. Peters
2008, Organic Geochemistry (39) 1137-1143
Insoluble solid bitumens are organic residues that can form by the thermal chemical alteration (TCA) or thermochemical sulfate reduction (TSR) of migrated petroleum. TCA may actually encompass several low temperature processes, such as biodegradation and asphaltene precipitation, followed by thermal alteration. TSR is an abiotic redox reaction where petroleum is...
Modeling distribution of dispersal distances in male white-tailed deer
Duane R. Diefenbach, E.S. Long, C.S. Rosenberry, B.D. Wallingford, D. R. Smith
2008, Journal of Wildlife Management (72) 1296-1303
Dispersal distances and their distribution pattern are important to understanding such phenomena as disease spread and gene flow, but oftentimes dispersal characteristics are modeled as a fixed trait for a given species. We found that dispersal distributions differ for spring and autumn dispersals of yearling male white-tailed deer (Odocoileus virginianus)...
Trends in snowpack chemistry and comparison to National Atmospheric Deposition Program results for the Rocky Mountains, US, 1993-2004
G.P. Ingersoll, M.A. Mast, K. Campbell, D. W. Clow, L. Nanus, J.T. Turk
2008, Atmospheric Environment (42) 6098-6113
Seasonal snowpack chemistry data from the Rocky Mountain region of the US was examined to identify long-term trends in concentration and chemical deposition in snow and in snow-water equivalent. For the period 1993-2004, comparisons of trends were made between 54 Rocky Mountain Snowpack sites and 16 National Atmospheric Deposition Program...
Ordovician sponges from west-central and east-central Alaska and western Yukon Territory, Canada
J.K. Rigby, R. B. Blodgett, B.B. Britt
2008, Bulletin of Geosciences (83) 153-168
Moderate collections of fossil sponges have been recovered over a several-year period from a few scattered localities in west-central and east-central Alaska, and from westernmost Yukon Territory of Canada. Two fragments of the demosponge agelasiid cliefdenellid, Cliefdenella alaskaensis Stock, 1981, and mostly small unidentifiable additional fragments were recovered from a...
A bioenergetic model for zebrafish Danio rerio (Hamilton)
C.J. Chizinski, Bibek Sharma, K.L. Pope, R. Patino
2008, Journal of Fish Biology (73) 35-43
A bioenergetics model was developed from observed consumption, respiration and growth rates for zebrafish Danio rerio across a range (18-32?? C) of water temperatures, and evaluated with a 50 day laboratory trial at 28?? C. No significant bias in variable estimates was found during the validation trial; namely, predicted zebrafish...
Nearshore habitat and fish community associations of coaster brook trout in Isle Royale, Lake Superior
O. T. Gorman, S.A. Moore, A.J. Carlson, H.R. Quinlan
2008, Transactions of the American Fisheries Society (137) 1252-1267
We characterized the nearshore habitat and fish community composition of approximately 300 km of shoreline within and adjacent to the major embayments of Isle Royale, Lake Superior. Sampling yielded 17 species, of which 12 were widespread and represented a common element of the Lake Superior fish community, including cisco Coregonus...
Classification tree models for predicting distributions of michigan stream fish from landscape variables
P.J. Steen, T.G. Zorn, P.W. Seelbach, J.S. Schaeffer
2008, Transactions of the American Fisheries Society (137) 976-996
Traditionally, fish habitat requirements have been described from local-scale environmental variables. However, recent studies have shown that studying landscape-scale processes improves our understanding of what drives species assemblages and distribution patterns across the landscape. Our goal was to learn more about constraints on the distribution of Michigan stream fish by...
Modeling axisymmetric flow and transport
C.D. Langevin
2008, Ground Water (46) 579-590
Unmodified versions of common computer programs such as MODFLOW, MT3DMS, and SEAWAT that use Cartesian geometry can accurately simulate axially symmetric ground water flow and solute transport. Axisymmetric flow and transport are simulated by adjusting several input parameters to account for the increase in flow area with radial distance from...
Genetic characterization of Kenai brown bears (Ursus arctos): Microsatellite and mitochondrial DNA control region variation in brown bears of the Kenai Peninsula, south central Alaska
J.V. Jackson, Sandra L. Talbot, S. Farley
2008, Canadian Journal of Zoology (86) 756-764
We collected data from 20 biparentally inherited microsatellite loci, and nucleotide sequence from the maternally inherited mitochondrial DNA (mtDNA) control region, to determine levels of genetic variation of the brown bears (Ursus arctos L., 1758) of the Kenai Peninsula, south central Alaska. Nuclear genetic variation was similar to that observed...
Inferences about ungulate population dynamics derived from age ratios
N.C. Harris, M. J. Kauffman, L. S. Mills
2008, Journal of Wildlife Management (72) 1143-1151
Age ratios (e.g., calf:cow for elk and fawn:doe for deer) are used regularly to monitor ungulate populations. However, it remains unclear what inferences are appropriate from this index because multiple vital rate changes can influence the observed ratio. We used modeling based on elk (Cervus elaphus) life-history to evaluate both...
Annual variation in habitat-specific recruitment success: Implications from an individual-based model of Lake Michigan alewife (Alosa pseudoharengus)
T.O. Hook, E.S. Rutherford, T.E. Croley II, D.M. Mason, C.P. Madenjian
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 1402-1412
The identification of important spawning and nursery habitats for fish stocks can aid fisheries management, but is complicated by various factors, including annual variation in recruitment success. The alewife (Alosa pseudoharengus) is an ecologically important species in Lake Michigan that utilizes a variety of habitats for spawning and early life...
Modeling the effects of wave skewness and beach cusps on littoral sand transport
K.A. Haas, L.A. Check, D.M. Hanes
2008, Journal of Coastal Research (24) 141-149
A process-based numerical modeling system is utilized for predicting littoral sand transport. The intent is to examine conditions slightly more complex than linear waves impinging upon a plane beach. Two factors that we examine are wave skewness and longshore varying bathymetry. An empirical model is used for calculating the skewed...
Importance of unsaturated zone flow for simulating recharge in a humid climate
R. J. Hunt, David E. Prudic, J.F. Walker, Marilyn P. Anderson
2008, Ground Water (46) 551-560
Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing...
Changes in the soil C cycle at the arid-hyperarid transition in the Atacama Desert
S.A. Ewing, J. L. Macalady, K. Warren-Rhodes, C.P. McKay, Ronald Amundson
2008, Journal of Geophysical Research G: Biogeosciences (113)
We examined soil organic C (OC) turnover and transport across the rainfall transition from a biotic, arid site to a largely abiotic, hyperarid site. With this transition, OC concentrations decrease, and C cycling slows precipitously, both in surface horizons and below ground. The concentration and isotopic character of soil OC...
Reactive flow models of the Anarraaq Zn-Pb-Ag deposit, Red Dog district, Alaska
C. Schardt, G. Garven, K.D. Kelley, D. L. Leach
2008, Mineralium Deposita (43) 735-757
The Red Dog ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations...
Data-resolution matrix and model-resolution matrix for Rayleigh-wave inversion using a damped least-squares method
J. Xia, R. D. Miller, Y. Xu
2008, Pure and Applied Geophysics (165) 1227-1248
Inversion of multimode surface-wave data is of increasing interest in the near-surface geophysics community. For a given near-surface geophysical problem, it is essential to understand how well the data, calculated according to a layered-earth model, might match the observed data. A data-resolution matrix is a function of the data kernel...
